US12031661B2 - Pipe reconditioning system - Google Patents

Abstract

A pipeline reconditioning system and process is provided for reconditioning corroded or damaged pipelines. The reconditioning system includes a mobile topside unit storing and providing reservoirs and supplies of substances used in the pipeline reconditioning and the equipment for the reconditioning system, a management and towing units that are securely anchored in the pipeline at remote access points, and a towed delivery system array that includes a deployment sled that processes the substances and dispenses the reconditioning material, such as a composite epoxy resin with chopped glass or basalt filament fibers, between access points to the pipeline interior.

Description

BACKGROUND OF THE DISCLOSURE

The development of high strength steel pipe technology has allowed for greater transmission of oil and gas due to the ability to increase internal pressure while decreasing the wall thickness of the pipe. API 5L X80 steel has excellent mechanical properties such as high strength, good toughness and good fatigue resistance.

However, when used for the transportation of oil and gas products (as well as other fluids such as water, sea water, chemicals, etc.), the integrity and operational efficiency of pipelines is subject to degradation due to corrosion. Historically, up to 63% of pipeline failures can be attributed to corrosion. Various pipe rupture statistics are shown below in Table 1.

TABLE 1
Pipe Rupture Comparison

	NEB	ERCB	PHMSA	EGIG
	(1991-2008)	(2000-2007)	(1987-2008)	(1970-2007)
	(%)	(%)	(%)	(%)
Corrosion	63%	7%	22%	15%
External	6%	49%	24%	50%
Interference
Material
	6%	28%	20%	17%
(Manufacturing
or Construction)
Geotechnical	6%	2%	5%	7%
Other Causes	19%	15%	29%	11%

Aged pipes can have several issues. Examples of causes of corrosion of apipe20 are illustrated inFIG.1, including internal corrosion21 (pitting or uniform corrosion), external corrosion22 (MIC, oxidation, under deposition), hydrogen induced cracking23, flow inducedcorrosion24 and cracking25 (stress corrosion cracking, embrittlement, sulfide corrosion cracking). While pipe manufacturers and operators seek to minimize corrosion damage to pipe through the use of powder coatings and fusion bond epoxy (FBE) applied prior to shipment, for example, these coatings and treatments can be damaged or degraded due to storage, handling and installation, as well as general operational wear and tear. This damage or degradation leads to the exposure of raw steel surfaces (both internal and external), which are then subjected to corrosive elements.

During the process of secondary oil recovery, which is becoming increasingly common, a large amount of produced water is generated which contains dissolved salts, inorganic and organic constituents, solids, oil, dissolved gases (CO₂and H₂S) and microorganisms. The dissolved gasses lead to the formation of corrosive acids and the microorganisms lead to biological damage.

Three types of corrosion can occur in oil and gas pipeline systems when carbon dioxide (CO₂) and hydrogen sulfide (H₂S) are present in the hydrocarbon fluid: sweet corrosion, sour corrosion and biological corrosion. Sweet corrosion occurs in systems containing only CO₂or a trace of H₂S (e.g., partial pressure <0.05 psi). Sour corrosion occurs in systems containing H₂S above a partial pressure of 0.05 psi and CO₂.

An example of a pipe with CO₂corrosion is shown inFIG.2A. When CO₂is present, the most common forms of corrosion include uniform corrosion, pitting corrosion, wormhole attack, galvanic ringworm corrosion, heat-affected corrosion, mesa attack, raindrop corrosion, erosion corrosion, and corrosion fatigue. The presence of carbon dioxide usually means no hydrogen embrittlement. CO₂corrosion rates are greater than the effect of carbonic acid alone. Corrosion rates in a CO₂system can reach very high levels (thousands of mils per year). CO₂corrosion of carbon steel used in oil production and transportation, when liquid water is present, is influenced by a large number of parameters, including: temperature, CO₂partial pressure, flow (flow regime and velocity), pH levels, concentration of dissolved corrosion product (e.g., FeCO₃), concentration of acetic acid, water wetting, metal microstructure (welds), metal prehistory (i.e., poor quality steel), and breakdown or damage to protective coatings.

H₂S often is present in wells drilled in shale or sandstone, or near coal or peat deposits or oil fields. H₂S combines with water to form sulfuric acid (H₂SO₄), a strongly corrosive acid. Corrosion due to H₂SO₄is often referred to as sour corrosion. Because H₂S combines easily with water, damage to pipelines can be aggressive and severe. An example of a pipe with H₂S corrosion is shown inFIG.2B.

The activity of microorganisms can change the nature of the aqueous environment which leads to hydrocarbon being degraded, clogging, souring and microbiologically induced corrosion (MIC), and more specifically the localized corrosion of pipeline steel. An example of a pipe with MIC is shown inFIG.2C.

Statistics regarding age distribution of U.S. pipeline infrastructure are provided in Table 2 below:

TABLE 2
Age Distribution of U.S. Pipeline Infrastructure
(Source: U.S. Dent, of Transportation)

		Gas Transmission	Hazardous	Gas Distribution
		and Gathering (%)	Liquid (%)	(%)
	2000s	9	8	19
	1990s	11	11	21
	1980s	10	9	16
	1970s	11	16	13
	1960s	24	21	15
	1950s	23	20	9
	1940s	8	8	2
	Pre-1940s	4	7	5

Various statistics regarding pipe failure are illustrated inFIGS.3A-3D (Source: Western University).FIG.3A shows the distribution of incidents due to third party excavation (TPE), external corrosion (EC), material failure (MF) and internal corrosion (IC) by the year of installation.FIG.3B shows the distribution of incidents by pipe diameter.FIG.3C shows the distribution of incidents by ignition and failure cause, including internal corrosion (IC), external corrosion (EC), third party excavation (TPE), first and second party excavation, (FSPE), previously damaged pipe (PDP), material failure (MF), earth movement (EM), and operations (O).FIG.3D shows a breakdown of fatalities and injuries by failure mode.

There are several problems with current pipe reconditioning processes. One such process is the insertion of liners. Liner insertion is primarily used for water and sewage pipes but can be used for a variety of applications. Thermoset liners (typically made of Polyvinylchloride (PVC) or Polyethylene (PE)) are dragged into place and inflated and cured using either steam, hot water or heated and pressurized air. While these liners do provide good flow (low drag) characteristics to pipes as well as a corrosive resistant internal boundary, their use is restricted to applications where there are short distances between pipe access points, the pipe does not carry any materials which have any abrasive materials, and the applications have lower pressure requirements. These characteristics mean that liners are unsuitable for long distance pipeline with extended distances (miles) between access points, which transport fluids which contain particulate (including crude oil) and require high pressure.

Other conventional reconditioning processes use a collection of equipment and processes to clear clogging materials and debris from the pipeline, clean and prepare the surface and then spray coat a corrosive resistant coating. These spray coats typically are polymers such as epoxies, polyurethanes or polyureas. However, all these existing processes employ a spray application only which severely limits their ability to fill the deeper recesses in the interior wall of the pipe created by corrosion, create a completely smooth and uniform internal wall surface to allow undisturbed laminar flow of pipeline fluids, replace the pressure containment strength of pipe wall lost to corrosion with a coating which provides inherent structural integrity, and compensate for additional containment strength lost to corrosion to the outside surfaces of the pipe. What is needed is an improved pipe reconditioning system that can prevent a majority of the causes of onshore and offshore hazardous liquid incidents, including onshore and offshore incidents as shown inFIGS.4A and4B, respectively (Source: U.S. Dept. of Transportation).

SUMMARY OF THE INVENTION

The present application addresses these shortcomings in the art by providing a manner of rebuilding the wall of a pipe from the inside with a corrosion free epoxy instead of coating the pipe. This solution provides: no erosion and corrosion, no coating failure, fastest time to operations, low installation costs, low maintenance costs, enhanced safety, no degradation of flow performance and no excavation.

The pipe reconditioning system of the present application can rebuild the wall of an aged corroded pipe from the inside of the pipe, maintain pipe integrity and performance, rebuild miles of pipe at a time (and eliminate connections), minimize pipe downtime, compensate for outer surface corrosion, control the minimum wall thickness, use epoxy with a reinforced chopped inorganic fiber blend, adjust the epoxy to supply thermal insulation, minimize flow friction and does not require certification.

The pipe reconditioning system of the present application provides several benefits, including that it can: fill the deeper recesses in the interior wall of the pipe created by corrosion, create a completely smooth and uniform internal wall surface for laminar fluid flow, replace the pressure containment strength of the pipe, create an epoxy layer of unrestricted thickness to allow for greater durability, increased pipeline safety and longer operational life, compensate for additional containment strength lost to corrosion to the outside surfaces of the pipe, provide optional thermal insulation, recondition vertical building pipes, allow field construction of new pipe, and dramatically reduce welded joints (and reduce failure points).

In accordance with an aspect of the present application, a pipeline reconditioning system is provided. The pipeline reconditioning system comprises a pipeline delivery system comprising a control unit and a towable deployment sled configured to deliver and dispense a layer of a reconditioning material to an inner surface of a pipeline; a topside unit comprising one or more material reservoirs and a plurality of spools of pipe for delivering materials from the one or more material reservoirs to the pipeline delivery system; and a delivery system management unit configured to be securely anchored in the pipeline at a first pipeline access point and to communicate with the control unit of the pipeline delivery system.

In accordance with one or more embodiments of the pipeline reconditioning system, the one or more material reservoirs comprise a reservoir of an epoxy resin; a source of glass or basalt chopped fibers; and a reservoir of a hardening material. The one or more material reservoirs further comprise a reservoir of a cleaning solvent configured to clean the pipeline prior to dispensing the reconditioning material.

In accordance with one or more additional or alternative embodiments of the pipeline reconditioning system, the topside unit is a mobile topside unit configured to be movable by a vehicle. The topside unit may also comprise a storage unit configured to store the pipeline delivery system.

In further embodiments of the pipeline reconditioning system, which may include any of the aforementioned embodiments, the towable deployment sled comprises a plurality of wheels and is secured to a towing cable in communication with the delivery system management unit, which is configured to tow the deployment sled towards the delivery system management unit while dispensing the reconditioning material. The pipeline delivery system receives a primary cable assembly from the topside unit and the delivery system management unit, the primary cable assembly comprising: a first pipe configured to carry the epoxy resin from the reservoir of the epoxy resin; a second pipe configured to carry the hardening material from the reservoir of the hardening material; the towing cable; a control cable configured to connect to the control unit of the pipeline delivery system; and a power cable configured to connect to the control unit of the pipeline delivery system and supply electric power to the pipeline delivery system from a power supply. The primary cable assembly may further comprise a supply line carrying the glass or basalt chopped fibers from the source of the glass or basalt chopped fibers. In various embodiments of the pipeline reconditioning system, the pipeline delivery system further comprises a mixing unit configured to mix together two or more of the epoxy resin, the glass or basalt chopped fibers, and the hardening material to create the reconditioning material to be applied to the inner surface of a pipeline. The towable deployment sled may comprise the mixing unit, one or more distribution passages configured to receive the reconditioning material from the mixing unit, and one or more pressurized distributors at ends of the one or more distribution passages configured to dispense and apply the layer of the reconditioning material to the inner surface of the pipeline. The one or more pressurized distributors may comprise a hinge mechanism comprising a plurality of spring-loaded panels connected to a body of the deployment sled and having curved tips, wherein the hinge mechanism is positioned in front of an opening dispensing the reconditioning material in the direction of travel of the deployment sled and is configured to block leakage of the reconditioning material in front of the opening.

In one embodiment of the pipeline reconditioning system, the one or more pressurized distributors further comprise: one or more nozzles configured to dispense the reconditioning material, and a guide blade configured to apply the reconditioning material to the inner surface of the pipe at a predetermined and consistent layer thickness. In another embodiment of the pipeline reconditioning system, the one or more pressurized distributors further comprise an extruder configured to dispense the reconditioning material at a predetermined and consistent layer thickness. In a further embodiment of the pipeline reconditioning system, the one or more pressurized distributors further comprise one or more nozzles configured to rotate circumferentially and dispense the layer of the reconditioning material to the inner surface of the pipeline. In a still further embodiment of the pipeline reconditioning system, the one or more pressurized distributors further comprise a plurality of nozzles arranged around a static disk configured to dispense the layer of the reconditioning material to the inner surface of the pipeline.

In various embodiments of the pipeline reconditioning system, including any of the aforementioned embodiments, the pipeline delivery system further comprises a curing device configured to cure the layer of reconditioning material applied to the inner surface of the pipeline with ultraviolet or microwave radiation.

In accordance with one or more additional or alternative embodiments of the pipeline reconditioning system, the delivery system management unit further comprises one or more sleds configured to be secured to the towing cable and provide the towing cable to the delivery system in the pipeline. The pipeline reconditioning system may also comprise a line towing unit arranged at a second pipeline access point, the line towing unit configured to supply a towing line into the pipeline configured to be transported to the first pipeline access point through the pipeline and to pull the primary cable assembly from the first pipeline access point to the second pipeline access point via the towing line, wherein the pipeline delivery system receives the primary cable assembly at the second pipeline access point and travels towards the first pipeline access point while dispensing the reconditioning material to the inner surface of the pipeline.

In accordance with a further aspect of the present application, a pipeline reconditioning method is provided, comprising: arranging within a pipeline, a pipeline delivery system comprising a control unit and a towable deployment sled configured to dispense a layer of a reconditioning material to an inner surface of the pipeline; providing one or more materials to the pipeline delivery system from one or more material reservoirs disposed in a topside unit comprising the one or more material reservoirs and a plurality of spools of pipe for delivering the one or materials from the one or more material reservoirs to the pipeline delivery system; and towing, by a delivery system management unit, the towable deployment sled through the pipeline while the towable deployment sled is dispensing the reconditioning material to the inner surface of the pipeline, the delivery system management unit comprising configured to be securely anchored in the pipeline at a first pipeline access point and to communicate with the control unit of the pipeline delivery system.

In one or more embodiments of the pipeline reconditioning method, the one or more materials provided to the pipeline delivery system comprise one or more of an epoxy resin, glass or basalt chopped fibers, and a hardening material. The method may further comprise mixing together the one or more materials provided to the pipeline delivery system by a mixing unit of the pipeline delivery system to create the reconditioning material to be applied to the inner surface of a pipeline. In further embodiments, the pipe reconditioning method also comprises dispensing and applying the layer of the reconditioning material to the inner surface of the pipeline by one or more pressurized distributors arranged on the deployment sled. In further embodiments, the pipe reconditioning method comprises curing the layer of the reconditioning material applied to the inner surface of the pipeline with ultraviolet or microwave radiation.

BRIEF DESCRIPTION OF THE FIGURES

FIG.1 shows examples of pipe corrosion;

FIG.2A shows an example of a pipe with carbon dioxide corrosion;

FIG.2B shows an example of a pipe with H₂S corrosion;

FIG.2C shows an example of a pipe with microbiologically induced corrosion;

FIGS.3A-3D show various statistics regarding pipe failure;

FIGS.4A-4B show various statistics regarding pipeline incidents;

FIGS.5A-5B show fluid flow characteristics post-reconditioning process using a conventional coating system and a pipe reconditioning system of the present application;

FIGS.6A and6B depict extracts fromFIGS.5A and5B, respectively;

FIG.6C show a reconditioned pipe having internal and external corrosion in accordance with an aspect of the pipe reconditioning system of the present application;

FIG.6D shows an example an extruded chopped filament pipe (EFCP) for new pipe installations in accordance with an aspect of the present application;

FIG.7 shows a mobile topside unit of a pipeline reconditioning system in accordance with an embodiment of the present application;

FIG.8 shows a delivery system management unit of a pipeline reconditioning system in accordance with an embodiment of the present application;

FIG.9A shows a towed robotic delivery system of a pipeline reconditioning system in accordance with an embodiment of the present application;

FIG.9B shows a side view of a hinge mechanism of the towed robotic delivery system of a pipeline reconditioning system in accordance with an embodiment of the present application;

FIG.9C shows an end view of a hinge mechanism of the towed robotic delivery system of a pipeline reconditioning system in accordance with an embodiment of the present application;

FIG.10 shows a towed robotic delivery system of a pipeline reconditioning system in accordance with a further embodiment of the present application;

FIG.11 shows a towed robotic delivery system of a pipeline reconditioning system in accordance with a further embodiment of the present application;

FIG.12A shows a nozzle mechanism towed robotic delivery system of a pipeline reconditioning system in accordance with an embodiment of the present application;

FIG.12B shows a nozzle mechanism towed robotic delivery system of a pipeline reconditioning system in accordance with a further embodiment of the present application;

FIGS.13A-13L show an example pipe reconditioning process for a horizontal operating sequence;

FIG.14 shows an example process of making an extruded chopped filament pipe using a towed robotic delivery system of a pipeline reconditioning system in accordance with a further embodiment of the present application;

FIG.15 shows an example of a continuous extruded chopped filament pipe manufacturing process in accordance with a further embodiment of the present application;

FIG.16 shows a cross-sectional view of a pipe load profile;

FIG.17 shows a cross-sectional circular extruded chopped filament pipe; and

FIG.18 shows a cross-sectional ovular extruded chopped filament pipe.

DETAILED DESCRIPTION OF THE INVENTION

The pipe reconditioning system of the present application will now be described with reference made toFIGS.5A-18.

FIGS.5A-6B illustrate fluid flow characteristics post-reconditioning process using conventional coating systems (FIGS.5A and6A) versus a pipe reconditioning system described herein (FIGS.5B and6B).

In thepipe50a, aconventional spray coating52ais applied against a heavily corrodedpipe wall51aprofile. While thecoating52acovers theinner pipe surface55a, the overallfluid flow profile53ais still uneven causing turbulent fluid flow. In contrast,FIGS.5B and6B illustrate a profile of rebuilding the interior55bof thewall51bof thepipe50bagainst thesame wall profile51a, by applying anepoxy layer coating52bthat may also include chopped fiber, using a pipe reconditioning process described herein. The reconditionedflow profile53bis even and smooth, allowing laminar fluid flow.

FIGS.6A and6B depict extracts fromFIGS.5A and5B, respectively. The Figures illustrate the structural strength of thepipe50a,50bafter the reconditioning process, and the improved distribution of load on thepipe wall51bin the case of deep wall corrosion.Conventional coating52awith epoxy will cover the corrodedsurface55aand provide corrosion protection; however, such acoating52awill not augment the pressure containment capacity of thepipe50aand will institutionalize a point of weakness and potential failure for the lifetime of thepipe50a.Full pipe pressure56ais exerted on all areas of fissure. Alayer52bof epoxy applied with the pipe reconditioning system described herein will re-establish structural integrity and pressure containment abilities by distributing reducedpressure56bover a larger surface area. Thicker layers52bof epoxy may be applied in a manner calculated to compensate for additional corrosion and erosion to theoutside surface54bof the pipe. The inclusion of chopped fiber in the epoxy can augment the structural strength of theepoxy layer52bbeing applied. The alignment of the fibers in the epoxy applied through a nozzle is designed for this purpose as another aspect of the application further augments the strength of thelayer52bof epoxy. A conventional spray coating system may not completely restore a clean profile to thesurface55aof thepipe50ain the case of deep pitting and fissures, and any recesses or hollows remaining will be subject to additional fatigue created by the changing pressure characteristics at that point caused by a breakdown in thelaminar flow53aof the fluid and ensuing turbulence at that point.

FIGS.6A and6B depict the deployment of coating and anepoxy layer52a,52bon the inside55a,55bof thepipe50a,50bto recondition thepipe50a,50b, but have been simplified and do not take into account the corrosion that also takes place on theoutside surface54a,54bof thepipe50a,50b. When taken together, these interior and exterior corrosion activities combine to incrementally reduce the pipe pressure containment capability (“PPCC”). Theconventional coating52ainFIG.6A provides little or no augmentation of the PPCC once that reconditioning process is completed. However, thelayer52bof epoxy, including chopped fiber for structural strength, deployed as part of the pipe reconditioning system ofFIGS.5B and6B restores structural strength.

As shown inFIG.6C, the combined effects of corrosion and erosion on the outerpipe wall surface54cand innerpipe wall surface55chave reduced the thickness of thepipe wall51cof the pipe from original wall thickness (x) to corroded wall thickness (y). With theincremental layer52cof epoxy containing chopped fiber (w) applied across thewhole surface55cof thepipe50c, the depth of the epoxy52cat the point of deepest corrosion is the effective restored wall thickness (z). As the thickness (w) increases, the overall PPCC of the pipe can re-establish the original pressure containment capability of thepipe50c, although the open cross section of thepipe50cwill be marginally diminished. Thepressure56cis reduced, being distributed over a larger surface area and an evenfluid flow profile53cis provided.

FIG.6D illustrates an example of the effectiveness in deploying epoxy using extruded chopped filament pipe (EFCP)50dfor new pipe installations. TheEFCP50dhas an outertrack pipe wall51d, which can be made of various materials including plastics, and an inner choppedfiber epoxy layer52d. Thepipe50dhas an evenfluid flow profile53d, withfull pipe pressure56dbeing exerted on the pipeinner surface55dand all areas of fissure.

The reconditioning portion of the process deploys the pipeline reconditioning system. The pipeline reconditioning system comprises amobile topside unit200, an example of which a shown inFIG.7, acontrol unit300 andtow unit305 securely anchored in thepipeline250 atremote access points260 and a towedarray400 comprising acontrol unit409, aresin system processor408 and adeployment sled405.

Themain topside unit200 may be a mobile, self-contained unit, as shown inFIG.7, which may comprise a control unit/sensor management device201, aprimary resin reservoir202, aprimary hardener reservoir203, cleaning solvent andflusher reservoirs204, finishing resin and hardener reservoirs205, sources of spooled glass and basalt206 for chopped fiber delivery, spooledpipe207 for resin delivery, spooledpipe208 for delivery of cleaning solvents and flushers, spooledsensor cables209, spooledtow cables215, spooledpower cables216, spooledpipe210 for hardener delivery, spooledpipes211 for finishing system delivery,storage212 for thepigs220,deployment sled405 and towedrobotic delivery system400 and a deliverysystem management unit300, including power systems and cable management systems. Themobile topside unit200 is towable by a truck or other vehicle, is able to move from onepipeline access point260 to the nextpipeline access point260.

An example of a deliverysystem management unit300 for the primary epoxy resin system deployment is shown inFIG.8. The deliverysystem management unit300 is arranged over and anchored at apipeline access point260. Aspool management trailer214 comprising least primaryresin delivery pipe207, primaryhardener delivery pipe210,tow cables215, control/sensor cables209power cables216 are provided with the deliverysystem management unit300. Collectively, these pipes and cables are included aprimary cable assembly213 for use by thedelivery system400 in thepipeline250. Theprimary cable assembly213 may include other cables and/or pipes as appropriate to provide a further input to thedelivery system400, including for example the chopped fiber206 or a pipe, delivery system or supply line for the same. An anchoredtow robot manager301 is provided inside thepipeline250, which provides theprimary cable assembly213 to thedelivery system400. One or more detachableload bearing sleds302 are provided, which can be attached to thetow cable215 approximately every thirty feet to support the weight of theprimary cable assembly213. Thecables209,215,216 andpipes207,210 supplied to the deliverysystem management unit300 can be extended or retracted into and out of thespool management trailer214 into thepipeline250 as needed using the deliverysystem management unit300.

Thedelivery system400, also referred to as a towed, robotic delivery system, is configured in thepipeline250 to deploy or delivery anepoxy402 inside of thepipe250 to recondition thepipe250. Thedelivery system400 comprises adeployment sled405 having a plurality ofguide wheels406 to move through thepipeline250 and one ormore sensors407. Theprimary cable assembly213 is provided to thedelivery system400 and aids in the primary operations of thedelivery system400. Theresin pipe207 and thehardener pipe210 are connected to the intake of amixing unit408 on thedeployment sled405, which receives the resin and hardener from thereservoirs202,203 and mixes them together for deployment. Other inputs may also be provided to themixing unit408 from themobile topside unit200, separately or in combination with theresin202 orhardener203, such as the cleaning, solvent or flushingfluids204, glass or basalt fibers206 or the finishing resin and/or hardener205. Themixer408 is in fluid communication with one ormore deployment passages408a, having anozzle404 or other pressurized deployment mechanism at their respective ends to distribute themixed epoxy402. Thetow cable215 is secured to a tow point on thedeployment sled405 and is configured to tow thedeployment sled405 towards the deliverysystem management unit300 and the anchoredtow robot manager301. Thecontrol cable209 andpower cable216 are connected to acontrol unit409 of thedelivery system400. Thepower cable216 supplies electric power to thedelivery system400 and its components, such as thesensors407, mixingunit408, andcontrol unit409 for example, from an above-ground power source, which may be in themanagement unit300. Thecontrol cables209 are configured to transmit control commands from the deliverysystem management unit300 and/or the control unit/sensor management device201 to thecontrol unit409 and send data and information from thecontrol unit409 to the deliverysystem management unit300 and/or the control unit/sensor management device201. For example, data and information from thesensors407 are processed by thecontrol unit409 and transmitted along thecontrol cable209. The deliverysystem management unit300 and the control unit/sensor management device201 may each comprise a computing device with memory and processor, which may comprise instructions for providing an automated operation of thedelivery system400 or may be manually operated by a user above ground. Afurther trailer cable410 is also connected to thedeployment sled405, which enters the pipeline from a separate access point, as shown inFIGS.13A-13L.

The design and configuration of thedeployment sled405 may vary depending on which resin system is being applied to theinternal surface251 of thepipe250. Initial surface cleaning, including treatment for under deposit corrosion and preparation may be performed by robotic pigs and/or other independently powered mechanisms (with or without towing mechanisms). During this process thepipeline250 may either be filled, sprayed or scoured with cleaningsolutions204. The epoxy deployed is a multi-part system which may include silicates and other particulate and is designed to be thixotropic, even in a pre-cured state. In another aspect of the application, the epoxy may include a photo initiator to cure the outer layer of the epoxy prior to completing curing ofepoxy layer252. Chopped fiber206 can be cut to specific lengths for the application and may include glass fiber, basalt fiber, and other suitable materials.

In one embodiment, the towedrobotic delivery system400 includes aguide401 which acts like a “Doctor Blade”, precisely deploying a continuous supply ofepoxy402 evenly and at a predetermined thickness across theinternal surface251 of thepipe250. An example of this embodiment is shown inFIG.9A. A managed buildup ofepoxy402 in front of the blade401 (in the direction of movement of the deployment sled405) ensures thatsufficient epoxy402 is available to fill even deep pitting and cavities in thepipe250.

Designed as an integral part of thedelivery system400, spring-loadedhinge mechanisms403 are attached to thebody405aof thedeployment sled405 at a point adjacent to, but just ahead of (relative to the direction of travel) thespecialty nozzles404 deploying theepoxy resin layer402 to theinternal surface251 of thepipe250. Examples of thehinge mechanism403 of thedelivery system400 are shown inFIGS.9B and9C. Since the epoxy402 is being deployed under pressure, it is critical that thesystem400 prevents leakage ahead of the sled405 (i.e., in the direction of travel identified by two parallel arrows inFIGS.9A,10 and11), and creates a consistent pressure ofepoxy402 delivery to the surface of thepipe250. The tips orplates403aof the spring-loadedpanels403bthat collectively make up thehinge mechanism403 are preferably curved to the radius of thepipe250, as shown inFIG.9C, and maintain constant contact with thesurface251 of thepipe250. A plurality ofplates403aand spring-loadedpanels403bare provided that can move independently from each other, so that their collective shape can conform toirregular surfaces251. Thetips403amay overlap and are also retractable towards thebody405aof thedeployment sled405 if there is a need to pull therobotic system400 back to the point of origin for any reason, such that they can be brought out of contact with thepipe surface251.

In another embodiment of the towedrobotic delivery system400ashown inFIG.10, thesystem400aincludes a trailed,extruder form411 which may have a wider opening than anozzle404 and which acts like a mold allowing for the deployment and forming of athicker layer252 ofepoxy402 evenly and at a predetermined thickness across theinternal surface251 of thepipe250.Sufficient epoxy402 is available to fill even deep pitting and cavities in thepipe250. A foaming agent may be added to increase the volume and penetration of theepoxy402. Anoptional curing mechanism412 can be added to thesystem400ato solidify thelayer252 ofepoxy402. Two examples of thecuring mechanism412 are ultraviolet radiation and microwaves.

Further embodiments of the towedrobotic delivery system400bof the pipe reconditioning system for adding a coating include the trailedarray system400bwith either (i) spinningnozzles413aor (ii) astatic disc413bwithmultiple nozzles413c, examples of which are shown inFIGS.11-12B. Each embodiment is designed to coat theinternal surface251 of thepipe250 with athin layer252 of a special coating. Thispipeline delivery system400bmay be used as a preventative measure for newer pipes. It may also be used as a final coating process after thepipe reconditioning system400,400a,400chas been used to deploy a corrosion resistant, resin coating that optimizes flow. Thissystem400bcan be used to deploy alayer252 of coating to reduce the drag effect of the pipe wall, reducing energy requirements for pumps, as shown for example inFIGS.12A and12B.FIG.12A illustrates a spinningnozzle413adesign geared to speed of travel of array for uniform coverage. Thespray arm413ais configured for full circumferential rotation and is customizable to diameter ofpipe250.FIG.12B illustrates a design havingmultiple nozzles413cattached tostatic disc413bcustomizable to diameter ofpipe250. Thenozzles413a,413cin each embodiment can be interchanged based upon flow rates, coverage and epoxy. Thedelivery system400bmay also be used to provide a coating of thesame epoxy402 as distributed by the previously discusseddelivery systems400,400a.

The orientation of chopped fiber changes the properties of pipe. The structural characteristics of a wound composite pipe is determined by the angle of the wound thread, the weight of the wound thread, the material of the wound thread, the epoxy used and the thickness of the pipe wall. The structural characteristics of a chopped fiber composite pipe is determined by the angle of the chopped fiber in the pipe wall, the weight of the chopped thread, the length of the chopped thread, the material of the wound thread, the epoxy used and the thickness of the pipe wall. The pipe reconditioning system adjusts the chopped thread orientation during the reconditioning to meet the application performance requirements. This can be done on a real time basis.

The pipe reconditioning process can comprise several steps, including: (1) internal pipeline assessment and reconditioning plan development, (2) conventional or mechanical pig excoriation, (3) debris removal, (4) pipeline cleaning and surface preparation, (5) pipeline surface assessment reconditioning plan finalization, (6) primary reconditioning pass performed using primary epoxy resin system based upon pipeline operating characteristics and requirements, (7) primary epoxy resin system including chopped fiber (E-CR glass, basalt or other fiber) to increase structural strength and fill larger cavities, (8) curing process which may include the use infrared, ultraviolet, microwave or e-beam radiation, steam, hot air or other gaseous mix, (9) pipeline assessment, (10) secondary reconditioning pass with secondary coating system designed to offer durability and exceptional low drag co-efficient surface, and (11) pipeline inspection and certification for service. It should be noted that depending on the requirements of thepipe250 requiring reconditioning, one or more of the above-identified steps can be omitted from the pipe reconditioning process.FIGS.13A-13L illustrate an example pipe reconditioning process for a horizontal operating sequence, including the above-referenced steps. The process can be performed using any of the previously discusseddelivery systems400,400a,400b, which are not limited to use with delivery of any particular materials described herein.

One of the key attributes of the pipe reconditioning process is that entire sections ofpipeline250 can be reconditioned between existing inspection or access points. A sequence of operations is described below between threeconsecutive access points260a,260b,260c, which can be arranged up to several kilometers apart.

In steps (1), (2) and (3) noted above, thepipeline250 is assessed and then cleared withconventional pigs220 driven by compressed air or water, and debris is removed, as shown inFIG.13A. Cleaning may involve “passivizing” the surface of the pipe wall, adjusting the pH and chloride levels with inhibited water runs, and solvent runs to dry the pipeline including the removal of under deposit corrosion. Step (4) noted above, pipeline cleaning and surface preparation, may be completed by autonomous robotic pigs ormultiple pigs220 operating in tandem powered by compressed air or water, as shown inFIG.13B. In step (5), detailed mapping and surface assessment of the pipeline is performed by a measuringunit221, a reconditioning plan is finalized, as shown inFIG.13C.

In step (6), a primary reconditioning pass is performed using a primary epoxy resin system based upon pipeline operating characteristics and requirements. As shown inFIG.13D, aline towing unit305 is positioned at thefirst access point260aand a deliverysystem management unit300 is positioned at thesecond access point260b, and acable towing unit414 pulls alight towing line410 fromaccess point260bto accesspoint260a. Theline towing unit305 then uses thelight towing line410 to pull a primary cable assembly213 (includingheavy tow cable215,resin pipe207,hardener pipe210,control sensor line209, and power cable216) fromaccess point260bto accesspoint260a, as shown inFIG.13E. The toweddelivery system400 is then positioned ataccess point260a, and attached to theprimary cable assembly213, as shown inFIG.13F. The deliverysystem management unit300 then pulls the towedrobotic delivery system400 fromaccess point260ato accesspoint260bandepoxy layer252 is deployed onpipeline250interior surface251. Thedelivery system400 also pulls towingline410 fromaccess point260ato accesspoint260b(FIG.13G). The deliverysystem management unit300 is then moved to thethird access point260cand theline towing unit305 to accesspoint260b, as shown inFIG.13H. The first section of treatedpipe252 is then sealed and cured253 using hot air, gas, steam or hot water, as shown inFIGS.131 and13J.

The process illustrated inFIG.13D is then repeated fromaccess point260cto accesspoint260b, whereby by a self-poweredrobot414 brings atowline410 fromaccess point260cto accesspoint260b, shown inFIGS.131 and13J. In one embodiment of the process, shown inFIG.13K, and as part of the process shown inFIG.13H, the towedrobotic delivery system400 may tow aUV emission system415. In this case, the epoxy402 will include a photo initiator, which, upon exposure to the UV radiation will cure the inner layer (furthest from outside pipe wall). Depth of penetration of UV radiation in an opaque medium is limited, however, thethin layer254 that is cured will serve to hold theepoxy layer252 securely in place (even though the epoxy402 is designed and formulated to be thixotropic) prior to a complete thermosetting cure being affected. The first section of pipe is now cured, and the process shown inFIG.13E is then repeated andprimary cable assembly213 is delivered to the towedrobotic delivery system400 ataccess point260b, as shown inFIG.13L. The next section of pipe can now be reconditioned, using the same process steps discussed above.

FIG.14 shows an example of extruded chopped filament pipe (ECFP)250aproduced in the field with adelivery system400c.ECFP250auses a thermoplasticouter pipe shell255a. Newcomposite pipe250acan be built in the field with all the reconditioned pipe benefits and eliminate connectors. Theouter shell pipe255aacts as guide or pipe form and may be disposable or may be designed to augment pressure and gas containment capabilities. Theouter pipe255acan be a cost-effective thermoplastic pipe, such as made from PVC. TheECFP250aeliminates cathodic and UV protection requirements. The contents of the epoxy402 can be adjusted to provide heat insulation for the hot water pipes. Moldedpipe250amay have multiple layers contributing individual and collective properties. Anepoxy pipe layer252acan have any wall thickness required. Connectors for thetrack pipe255aare simple and easy to install. The system can also be used to manufacture molded pipe in a factory. Internal epoxy layers252acan be joined and sealed in the field at installations using a complementary epoxy gasket and adhesive. The process coats thepipe250awith a durable, corrosion resistantepoxy resin layer252a, effectively creating a new pipe.

FIG.15 shows an example of a continuous ECFP manufacturing process having a stationary robot system with extruder form. Areservoir202bfor the chopped fiber and epoxy is provided, which spools or weaves a seamless,ECFP252b. The spooling or weaving may be done on or adjacent to abarge256 for off-shore pipe or atruck bed256 for on-shore pipe. A thermoplasticouter pipe255bis provided, with aslit255calong its length, which can be arranged over and around theECFP252b. Theslit255ccan then be sealed to close theouter pipe255b.

Because the ECFP as well as the pipe reconditioning system use a form to apply the epoxy system to the wall of the pipe, in another aspect of the invention, the shape of the form can be altered to suit specific purposes. The circular shape of the pipe can be retained using a circular form where the internal diameter of the pipe (D₁) minus the diameter of the form (D₂) divided by 2 will give the consistent thickness of the epoxy system (w) where (D₁−D₂)/2=w. Where, for example there are high levels of corrosion in the side walls of the target pipe and where the pipe is subsurface and subject to compression, increasing the thickness of the epoxy system on the side walls of the pipe may be optimal. Euler's critical load, which is the maximum load which a column (or pipe wall) can bear is defined by:

$P_{\mathrm{cr}}=\frac{{\pi }^2\mathrm{EI}}{{\left(\mathrm{KL}\right)}^2}$
wherein:

• • P_cr=Euler's critical load (longitudinal compression load on column),
  • E=modulus of elasticity of column material,
  • I=minimum area moment of inertia of the cross section of the column,
  • L=unsupported length of column, and
  • K=column effective length factor.

The critical load capacity (P_cr) may be increased by increasing the cross section of the wall (I). The maximum points of tension on the pipe wall under combined loading are at (a) and (b) of thepipe250bshown inFIG.16, Where: δ=deflection in pipe diameter due to compression stress; P=internal pressure of pipe; D=original diameter of pipe; C=compression stress. Therefore, in order to offset the tension at points (a) and (b) and increase P_cr, the pipe shape can be modified from acircular shape257a(FIG.17) tooval shape257b(FIG.18).

The pipe reconditioning system can be used for a wide variety of existing pipe installations, including carbon steel, galvanized steel, cast iron, concrete, thermoplastic (i.e., PP, PVC etc.) (may be used to add pressure capability or thermal insulation), Hybrids (including metallic/non-metallic combinations) and composite. The system may be also used in combination with any of the above materials to make new pipe, either in the factory or on-site to create pipe which has the performance capability which either meets or exceeds that of reconditioned pipe. The systems of the present application may be used with the pipes described in International Patent Application Nos. PCT/US2016/052822 (filed Sep. 21, 2016), PCT/US2016/019068 (filed Feb. 23, 2016) and PCT/US2016/019077 (filed Feb. 23, 2016), which are each incorporated by reference in their entireties.

The pipe reconditioning system can also be used for vertical pipe applications. In buildings there are corroded pipes that exist in both a vertical and horizontal orientation. The horizontal operating sequence can be modified for the vertical pipes. The epoxy can be adjusted to provide internal heat insulation for the hot water pipes.

It should be understood that, unless stated otherwise herein, any of the features, characteristics, alternatives or modifications described regarding a particular embodiment herein may also be applied, used, or incorporated with any other embodiment described herein. Also, the drawing herein is not drawn to scale. Although the invention has been described and illustrated with respect to exemplary embodiments thereof, the foregoing and various other additions and omissions may be made therein and thereto without departing from the spirit and scope of the present invention.

Claims (20)

What is claimed:

1. A pipeline reconditioning system comprising:

a pipeline delivery system comprising a control unit and a towable deployment sled configured to deliver and dispense a layer of a reconditioning material to an inner surface of a pipeline;

a topside unit comprising one or more material reservoirs and a plurality of spools of pipe for delivering materials from the one or more material reservoirs to the pipeline delivery system; and

a delivery system management unit configured to be securely anchored in the pipeline at a first pipeline access point and to communicate with the control unit of the pipeline delivery system.

2. The pipeline reconditioning system according toclaim 1, wherein the one or more material reservoirs comprise:

a reservoir of an epoxy resin;

a source of glass or basalt chopped fibers; and

a reservoir of a hardening material.

3. The pipeline reconditioning system according toclaim 2, wherein the one or more material reservoirs further comprise a reservoir of a cleaning solvent configured to clean the pipeline prior to dispensing the reconditioning material.

4. The pipeline reconditioning system according toclaim 1, wherein the topside unit is a mobile topside unit configured to be movable by a vehicle.

5. The pipeline reconditioning system according toclaim 1, wherein the topside unit further comprises a storage unit configured to store the pipeline delivery system.

6. The pipeline reconditioning system according toclaim 1, wherein the towable deployment sled comprises a plurality of wheels and is secured to a towing cable in communication with the delivery system management unit, which is configured to tow the deployment sled towards the delivery system management unit while dispensing the reconditioning material.

7. The pipeline reconditioning system according toclaim 2, wherein the pipeline delivery system receives a primary cable assembly from the topside unit and the delivery system management unit, the primary cable assembly comprising:

a first pipe configured to carry the epoxy resin from the reservoir of the epoxy resin;

a second pipe configured to carry the hardening material from the reservoir of the hardening material;

a towing cable;

a control cable configured to connect to the control unit of the pipeline delivery system; and

a power cable configured to connect to the control unit of the pipeline delivery system and supply electric power to the pipeline delivery system from a power supply.

8. The pipeline reconditioning system according toclaim 7, wherein the primary cable assembly further comprises a supply line carrying the glass or basalt chopped fibers from the source of the glass or basalt chopped fibers.

9. The pipeline reconditioning system according toclaim 8, wherein the pipeline delivery system further comprises a mixing unit configured to mix together two or more of the epoxy resin, the glass or basalt chopped fibers, and the hardening material to create the reconditioning material to be applied to the inner surface of a pipeline.

10. The pipeline reconditioning system according toclaim 9, wherein the towable deployment sled comprises:

the mixing unit;

one or more distribution passages configured to receive the reconditioning material from the mixing unit; and

one or more pressurized distributors at ends of the one or more distribution passages configured to dispense and apply the layer of the reconditioning material to the inner surface of the pipeline.

11. The pipeline reconditioning system according toclaim 10, wherein the one or more pressurized distributors comprise a hinge mechanism comprising a plurality of spring-loaded panels connected to a body of the deployment sled and having curved tips, wherein the hinge mechanism is positioned in front of an opening dispensing the reconditioning material in a direction of travel of the deployment sled and is configured to block leakage of the reconditioning material in front of the opening.

12. The pipeline reconditioning system according toclaim 11, wherein the one or more pressurized distributors further comprise:

one or more nozzles configured to dispense the reconditioning material; and

a guide blade configured to apply the reconditioning material to the inner surface of the pipeline at a predetermined and consistent layer thickness.

13. The pipeline reconditioning system according toclaim 11, wherein the one or more pressurized distributors further comprise an extruder configured to dispense the reconditioning material at a predetermined and consistent layer thickness.

14. The pipeline reconditioning system according toclaim 11, wherein the one or more pressurized distributors further comprise:

one or more nozzles configured to rotate circumferentially and dispense the layer of the reconditioning material to the inner surface of the pipeline.

15. The pipeline reconditioning system according toclaim 11, wherein the one or more pressurized distributors further comprise:

a plurality of nozzles arranged around a static disk configured to dispense the layer of the reconditioning material to the inner surface of the pipeline.

16. The pipeline reconditioning system according toclaim 1, wherein the pipeline delivery system further comprises a curing device configured to cure the layer of reconditioning material applied to the inner surface of the pipeline with ultraviolet or microwave radiation.

17. The pipeline reconditioning system according toclaim 7, wherein the delivery system management unit further comprises one or more sleds configured to be secured to the towing cable and provide the towing cable to the pipeline delivery system in the pipeline.

18. The pipeline reconditioning system according toclaim 7, further comprising a line towing unit arranged at a second pipeline access point, the line towing unit configured to supply a towing line into the pipeline configured to be transported to the first pipeline access point through the pipeline and to pull the primary cable assembly from the first pipeline access point to the second pipeline access point via the towing line, wherein the pipeline delivery system receives the primary cable assembly at the second pipeline access point and travels towards the first pipeline access point while dispensing the reconditioning material to the inner surface of the pipeline.

19. A pipeline reconditioning method comprising:

arranging within a pipeline, a pipeline delivery system comprising a control unit and a towable deployment sled configured to dispense a layer of a reconditioning material to an inner surface of the pipeline;

providing one or more materials to the pipeline delivery system from one or more material reservoirs disposed in a topside unit comprising the one or more material reservoirs and a plurality of spools of pipe for delivering the one or materials from the one or more material reservoirs to the pipeline delivery system; and

towing, by a delivery system management unit, the towable deployment sled through the pipeline while the towable deployment sled is dispensing the reconditioning material to the inner surface of the pipeline, the delivery system management unit comprising configured to be securely anchored in the pipeline at a first pipeline access point and to communicate with the control unit of the pipeline delivery system.

20. The pipeline reconditioning method according toclaim 19, wherein the one or more materials provided to the pipeline delivery system comprise one or more of an epoxy resin, glass or basalt chopped fibers, and a hardening material, and wherein the method further comprises:

mixing together the one or more materials provided to the pipeline delivery system by a mixing unit of the pipeline delivery system to create the reconditioning material to be applied to the inner surface of a pipeline;

dispensing and applying the layer of the reconditioning material to the inner surface of the pipeline by one or more pressurized distributors arranged on the deployment sled; and

curing the layer of the reconditioning material applied to the inner surface of the pipeline with ultraviolet or microwave radiation.

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